Abstracts

Rationale: Vagus nerve stimulation (VNS) is an adjunctive treatment for refractory epilepsy. Patients with VNS typically have severe epilepsy and may have greater medical comorbidity than similarly aged cohorts. The VNS device can complicate the management of comorbid conditions as some procedures are contraindicated by the device, or will require additional safeguards. To date, there have been few studies describing epilepsy sequelae and comorbidity in the VNS treated patient population. This study aimed to identify major health issues in patients with refractory epilepsy treated with long-term VNS.Methods: A retrospective analysis of major health issues, including significant medical issues and side effects, was performed in a cohort of 52 epilepsy patients treated with VNS. Significant medical issues were defined as myocardial infarction, cerebrovascular accident, cancer, chronic pulmonary conditions, chronic gastrointestinal conditions, acute pulmonary events, acute gastrointestinal events, seizure-related injury, suicide attempt, and death.Results: The mean age at VNS initiation and time of study was 39.5 and 48.3 years, respectively. Mean duration of therapy was 8.9 years. Side effects limiting therapy were observed in 15.4% of patients. At least one significant medical issue was seen in 38.5% of patients. Death (19.2%), seizure-related injury (15.4%), chronic pulmonary conditions (11.5%), and acute pulmonary events (9.6%) were most commonly observed. Death occurred after a mean 8.3 years of VNS therapy at 54.9 years of age, attributable to cancer in three (5.7%) cases and likely to sudden unexpected death in epilepsy (SUDEP) in two (3.8%) cases. Lack of follow-up limited VNS management in 25.0% of patients, representing an additional challenge in this population. The VNS device mitigated medical management in five cases, including three cancers, one pulmonary, and one emergency surgery.Conclusions: While some illness may be anticipated due to aging and epilepsy refractory to treatment, comorbidity and mortality in this cohort were greater than expected. Consequently, knowledge of how VNS impacts medical management in both acute care and outpatient settings is essential. Furthermore, medical comorbidity may have been under-recognized as about a quarter of this cohort became lost to follow-up for at least two years prior to the time of study.